Insulin is a hormone that is produced in the body. It works by lowering levels of glucose (sugar) in the blood. Insulin lispro is a fast-acting form of insulin.

Insulin lispro is used to treat type 1 (insulin-dependent) diabetes in adults. It is usually given together with another long-acting insulin.

Insulin lispro is also used together with oral (taken by mouth) medications to treat type 2 (non insulin-dependent) diabetes in adults.

Insulin lispro may also be used for other purposes not listed in this medication guide.

What are the possible side effects of insulin lispro (Humalog, Humalog Cartridge, Humalog KwikPen, Humalog Pen)?

Get emergency medical help if you have any of these signs of insulin allergy: itching skin rash over the entire body, wheezing, trouble breathing, fast heart rate, sweating, or feeling like you might pass out.

Hypoglycemia, or low blood sugar, is the most common side effect of insulin lispro. Symptoms of low blood sugar may include headache, nausea, hunger, confusion, drowsiness, weakness, dizziness, blurred vision, fast heartbeat, sweating, tremor, trouble concentrating, confusion, or seizure (convulsions). Watch for signs of low blood sugar. Carry a piece of non-dietetic hard candy or glucose tablets with you in case you have low blood sugar.

Insulin lispro can also cause hypokalemia (low potassium levels in the blood). Call your doctor at once if you have symptoms such as dry mouth, increased thirst, increased urination, uneven heartbeats, muscle pain or weakness, leg pain or discomfort, or confusion.

Tell your doctor if you have itching, swelling, redness, or thickening of the skin where you inject insulin lispro.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

What is the most important information I should know about insulin lispro (Humalog, Humalog Cartridge, Humalog KwikPen, Humalog Pen)?

Insulin lispro is a fast-acting insulin that begins to work very quickly. If you use this medication with meal, use it within 15 minutes before or just after you eat.

Take care to keep your blood sugar from getting too low, causing hypoglycemia. Symptoms of low blood sugar may include headache, nausea, hunger, confusion, drowsiness, weakness, dizziness, blurred vision, fast heartbeat, sweating, tremor, or trouble concentrating. Carry a piece of non-dietetic hard candy or glucose tablets with you in case you have low blood sugar. Also be sure your family and close friends know how to help you in an emergency.

Never share an injection pen or cartridge with another person. Sharing injection pens or cartridges can allow disease such as hepatitis or HIV to pass from one person to another.

Insulin lispro is only part of a complete program of treatment that may also include diet, exercise, weight control, foot care, eye care, dental care, and testing your blood sugar. Follow your diet, medication, and exercise routines very closely. Changing any of these factors can affect your blood sugar levels.